The present invention relates to a composite body comprising a hub, an outer ring, and a synthetic resin material interposed between the hub and the outer ring. Devices of this general type are disclosed, for example, in published German patent application no. DE 26 28 826 or in United Kingdom patent specification no. GB 243,518.
In DE 26 28 826, the composite body, which is constructed as a torque-transmitting gear wheel, comprises a radially inner hub body, which is provided with external profiles and can be placed with the aid of an inner recess thereof on a shaft and an outer body, which is provided at a radial distance from the hub body, in the form of a gear rim comprising internal profiles, and an intermediate layer provided between the internal and external profiles, and an insulating layer which is intended to perform a damping function and represent an electrical insulation. The inner and outer bodies are fitted on the insulating layer provided between them.
In GB 243,518, the outer part is likewise a gear rim comprising outwardly oriented teeth and inwardly oriented projections. The inner hub body is a flange-like body with axial holes. The synthetic material inserted between the two parts connects the two parts, whereby an interlocking engagement is produced by way of the holes provided in the flange of the inner part in addition to the existing adhesive force in order to transmit torque from or to the hub body. The torque is likewise transmitted from or to the gear rim initially by way of the adhesive force and additionally by interlocking engagement by way of the radially inwardly oriented regions of the gear rim and the plastic regions located therebetween.
The devices disclosed in both the published German patent application and the United Kingdom patent specification suffer from the disadvantage of high production cost, particularly due to the necessary forming and machining operations of the metal parts. In the case of the devices disclosed in the United Kingdom patent specification, the steel hub 3 must be flanged in order to receive the edge 6, and the edge 6 must be knurled elaborately in order to ensure very good contact with the molded compound 4. The holes 7 must either be punched or drilled.
The sharp-edged profiles known from the published German patent application can be produced only by machining operations, e.g., by broaching.
Another disadvantage of the devices disclosed in the United Kingdom patent specification is that the plastic plugs extending through the openings in the flange enable only a relatively small torque transmission because the torque transmitting surface is relatively small. Furthermore, the plugs extending axially through the flange may be sheared off in the case of sudden applications of torque forces.
Teeth, such as those depicted in the published German patent application, are more advantageous in this respect; however, they necessitate higher production costs, as mentioned above.